Generally, large and medium sized buildings such as an office tower, a public institution building, and an apartment are provided with building facilities such as an air conditioner, a boiler, and a pump to control the temperature and humidity of air in a room and to purify the air, thereby keeping the environment of the room suitable for intended use.
The buildings are also provided with a building automation system for controlling the building facilities. Generally, such a building automation system includes a direct digital controller (DDC), which is a local controller.
Such a direct digital controller (DDC) collects and sends information necessary for temperature/humidity control of a heating and air conditioning system, monitoring/controlling/reporting operation status of building facilities, energy measurement and management, monitoring/controlling a power system, a security alarm system and a fire fighting system.
However, a typical direct digital controller adapted to control the entire building automation system has a problem in that control and management over the building automation system are impossible when an algorithm executing unit of the direct digital controller malfunctions.
In addition, since such a typical direct digital controller is hardwired to other components, there are concerns of performance deterioration over time, high maintenance cost, generation of crosstalk-induced noise, increase in possibility of lightning strike, and the like.
Further, for the typical direct digital controller, it is difficult to change the position of existing equipment when remodeling, and additional cabling work is required when extending the equipment, causes increase in construction period and cost.